We noticed this yesterday while ground testing PIDs in FBWA with some airspeed spoofing with a blower. The integrator would wind up (too much, but that was on purpose for learning and testing) and then we switched to Manual mode. We stayed in Manual mode for a little while and then switched back to FBWA. Well the elevator snapped right back to the previous “trim” that the integrator had put in. From what I am reading from the 2 reset_I() methods, that shouldn’t have happened.
ArduPlane 3.9.8 on a CubeBlack